© Jochen Voß / LLUR
MEKUN: Protecting the oceans
The invisible danger – hazardous substances in seawater and seabed
MEKUN's Marine Protection Unit monitors which chemical pollutants enter our marine environment, where they come from, in what quantities, if they exceed critical thresholds and whether pollution is decreasing or increasing over time.
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Water sampler on a rosette with probes for temperature, conductivity, depth and other parameters if required.
The list of hazardous substances is long - biocides, polybrominated diphenyl ethers (PBDEs) and per- and polyfluoroalkyl substances (PFAS) are just a few examples. Many of these substances are found everywhere and are not degraded in the environment or only very slowly. They usually spread via the water or air and then accumulate in the (marine) soil or in living organisms and, thus, enter the food chain. Due to the often toxic, carcinogenic or hormonal effects of the pollutants, they pose a risk to humans and our environment. Some pollutants have an acute effect (e.g. toxins such as copper from anti-fouling products from shipping can act as cell toxins), others affect reproduction (e.g. organotin compounds such as tributyltin (TBT)) and still others lead to chronic impairments (e.g. mercury damages the nervous system) or a shortened lifespan (e.g. carcinogenic polycyclic aromatic hydrocarbons (PAHs) such as naphthalene). The environmental status of both the German Baltic Sea and the North Sea is rated as poor in terms of chemical pollution.
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Laboratory on the MS Haithabu.
Host City Local Partner
The Ocean Race Europe 2025
Where do the hazardous substances come from?
Hazardous substances enter our ocean via discharges (e.g. from sewage treatment plants and industry), rivers, the air or sources on and in the sea (e.g. oil spills, munitions, anti-fouling products in shipping). They originate from flame retardants (e.g. PBDEs), the incineration of waste and fossil fuels (e.g. heavy metals, PAHs), the use of pesticides (e.g. TBT), biocides (e.g. copper) and medicines, or the industrial manufacture or use of products with special properties (e.g. the water and grease-repellent PFAS in non-stick coatings, lubricants or fire extinguishing foams).
What does boating have to do with it?
The more saline the water, the more boat hull fouling is a problem for water sports enthusiasts. The growth of organisms (fouling) both slows down the journey, and also increases fuel consumption. To protect hulls from fouling, toxic biocides are usually used. Many anti-fouling products contain copper, for example, which also has a toxic effect in the marine environment beyond the hull of the boat. In 2012, with a good 70 tonnes, almost 1/5 of the total copper load in surface waters nationwide was caused by anti-fouling products in the recreational boating sector. Copper accumulates in sediment and over large areas of the Baltic Sea exceeds the threshold value adopted by HELCOM in the Marine Strategy Framework Directive (MSFD), above which biological effects are to be expected. There is a lack of data for coastal waters and the North Sea.
Can hazardous substances be removed from the environment?
Only to a very small extent. Because many substances are persistent (difficult to break down) and therefore accumulate in the environment, they will still be found in the marine environment for a long time even after a ban. Their molecular size and, above all, the fact that they are distributed virtually everywhere by water and the atmosphere - dissolved or bound to particles such as microplastics or dust - makes it impossible to ‘collect’ the chemical pollutants again once they have been released. This makes it all the more important to comply with bans and the precautionary principle and to avoid introducing known or potentially harmful substances into the environment.
What can I do in boating or in general?
• Be mindful and choose environmentally friendly products (e.g. biocide-free or low-biocide anti-fouling products adapted to the salinity of your sporting area; PFAS-free functional clothing; biodegradable hygiene products);
• Cover boat hulls in hard coatings that can be mechanically cleaned of fouling with underwater brushes or ultrasound;
• Store boats on dry land when not in use to prevent biofouling;
• follow existing recommendations, e.g. the background paper from the German Federal Environment Agency, which provides information on antifouling coatings and substance inputs and gives recommendations for environmentally friendly use (in German), or the ‘Guide on best practices of biofouling management in the Baltic Sea’ from OSPAR & HELCOM (in English);
• expand your knowledge, e.g. through the fun and free e-learning course on biofouling and antifouling for recreational craft (in German), or through the biofouling information provided by the German Federal Maritime and Hydrographic Agency (BSH; in German);
• demand and support bans and restrictions on industrial use and the adaptation of production processes, e.g. at EU level or with regional political representatives.
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